SPAM EMAILS BEING SENT

Hello I am having a problem with the YITH Rewards plugin. For some reason it keeps spamming all of our customers, It keeps sending customers that their points are expiring, except it send customers multiple emails a day of points completely irrelevant to the customer. I deleted this plugin and for some reason these emails are not stopping. Our customers have been complaining about these emails for the past few days. How is it possible that the plugin is deleted and that the points expiring emails are still being sent and to the wrong customers as well?